Referring to FIG. 8, a cat wears a collar 62 with a conventional safety device 63. Referring to FIG. 9, the conventional safety device 63 is configured like a buckle of a waist belt. The conventional safety device 63 includes a female member 64 and a male member 65. The female member 64 includes a first plate 67 and a second plate 68. A space 69 is defined between the plates 67 and 68. The second plate 68 defines a recess 70 with a reduced open end. The male member 65 includes a plate 71 and a mushroom-shaped portion 66 formed on the plate 71. To engage the male member 65 with the female member 64, the plate 71 and the mushroom-shaped portion 66 are inserted into the space 69 and the recess 70, respectively. In case that the collar 62 is entangled with a branch of a tree for example, the male member 65 is supposed to be disengaged from the female member 64 in order to prevent the collar 62 from strangling the cat. However, several problems are encountered in the use of the conventional safety device 63. Firstly, unless the conventional safety device 63 is subject to a force that is oriented precisely and large enough, the male member 65 cannot be disengaged from the female member 64. Moreover, the male member 65 cannot be pivoted relative to the female member 64 in compliance with the neck of the cat. Thus, the cat feels uncomfortable wearing the collar 62 with the safety device 63.
Therefore, the present invention is intended to obviate or at least alleviate the problems encountered in the prior art.